Grinding-machine



A. JOHNSTON. GRINDING MACHINE.

4 Sheets-Sheet 1.

(No Model.)

No. 504,389. Patented Sept. 5, 1893.

- No Model) 4.Sheets"-Sh eet 2.

' A. JOHNSTON.

. RINDING MACHINE.

(No Model.) v 4 Sheets-Sheet 4.

A. JOHNSTON.

GRINDING MACHINE.

Nd. 504,889. Patented Sept. 5, 189 3,

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& ik z V 0 g I a l u a 2 j z Q 2 m "It; m 4 a 5- p 1 I I '7 L5 5? 6 3UNITED STATES PATENT OFFICE.

ALLEN JOHNSTON, OF OTTUMWA, IOWA.

GRINDING- MACHINE.

SPEGIFICATION forming part of Letters Patent No. 504,389, datedSeptember 5, 1893.

Application filed May 12, 1893. Serial No. 473,991. (No model.)

To all whom it may concenn;

Be it known that I, ALLEN JOHNSTON, of Ottumwa, Iowa, have invented anew and useful Improvement in Grinding-Machines, which is fully setforth in the following specification.

This invention relates to the .construction of grinding machinesemploying cup-shaped or ring grinding wheels, the machine being of thesame general character as that described in Letters-Patent No. 465,478,granted to me December 22, 1891.

The general object of the invention, which is attained in theconstruction of the machine as hereinafter explained, is to facilitatethe grinding of iron and steel surfaces, to improve the character of thework, and to effect economy in the operation. According to the presentinvention the cup -shaped or ring grinder is supported in an invertedposition so that its grinding surface is underneath, and the work-holderis beneath the wheel, instead of above or at one side, as usuallyarranged heretofore. This arrangement is of great practical utility. Itpermits the workman to keep the operation of the grinder upon the workunder constant observation and to note how the wheel is cutting at eachreciprocation of the feed. In many cases it avoids the necessity ofchecking or clamping the work. On this account the grinding of certainclasses of articles .is greatly expedited. In the case, for example, ofdie-blocks or plates which require the whole surface to be cut it isonly necessary to employ holding pins at the sides of the article, whichis dropped into its place on the holder, ground and removed withoutdelay. Moreover, this arrangement of the wheel facilitates theapplication of the water in regulated quantity. The water is suppliedfrom above through the hollow wheel in regulated quantity, and beingspread evenly around the wheel by centrifugal action, falls upon thework at the place where the grinding is being done.

The invention furthermore consists in mounting the wheel upon ahorizontal reciprocating bed, and combining it with a stationarywork-holder; although many of the improvements are applicable as well tomachines in which the work-holder reciprocates and the wheel isstationary. The bed-carrying the wheel is hollow, and embraces the vwork-holder which is in the form of a vertical column, provided withmeans for adj usting it toward and away from the wheel.

The invention includes a particular mode of mounting the wheel so as tosustain the end thrust. In using cup-shaped or ring grinders (whetherthe axis be horizontal or perpendicular) it is evident that the greatpressure and wear is in line of the axis of the wheel, and as it ispractically impossible to keep the end of a shaft or spindle oiled theoperation of cup-grinders has been attended with difficulty, and withexcessive friction and wear. In ordinary grinders, which grind on theedge or periphery, the thrust is lateral to the axis, and this is moreeasily provided for. Moreover, to produce the best results withcup-grinders there must be no end play, which would afiect the depth ofout. This fact also distinguishes a cup-grinder from an ordinaryedge-grinder, as in the latter case slight end 7 play is more easilyavoided, and if it occurs is of little consequence. I have succeeded inavoiding the difficulty of end thrust by mounting the hub or support ofthe wheel, or its spindle (according to the special constructionemployed) upon ball bearings. In order to provide against end-play andwear, and the effect of expansion and contractionl employ two sets ofballs which are on opposite sides of a circular plate or ring turningwith the wheel, and means are provided for pressing the two series ofballs toward each other, so as to hold the plate, and consequently thewheel, firmly against end play.

The invention includes other features of construction, as well ascombinations of the seiveral parts or elements as hereinafter pointeout.

I will now describe one form of grinding machine in which the presentinvention is embodied, reference being bad to the accompanying drawingswhich form part of this specification, and in which- Figure I, is afront elevation; Fig. II, a plan view; Fig. III, a vertical longitudinalsection; Fig. IV, a vertical section on line IV (Fig. III); Fig. V, avertical section on lineV (Fig. I), and Fig. VI, a detail of a springpin.

A represents the main frame which is a casting whose shape is clearlyshown and requires no description. It has horizontal upper edges Cb andunder-cut grooves a constituting guides and slide-ways for the bed B,which carries the grinder 0. As shown in the cr0ss-section views (Figs.IV and V) the upper part of the main frame is trough-shaped and the bedB is set within the two sides of the frame. Along the sides of the bed Bare horizontal ribs 1), b which fit into the guides of the main frame insuch manner as to permit movement of the bed in a longitudinal directiononly. Bed B is oblong and is entirely closed on the sides and ends. Ontop it has an opening D for introduction of the work and underneathanother opening E for admission of the Vertical column F which supportsthe work-holder.

The grinding wheel C, which is of the cup or ring form is supported uponthe reciprocating bed B in an inverted position, so that its grindingsurface is undermost. It is mounted upon a supporting ring or base 0',and the latter is attached to the driving pulley G by means ofhook-bolts g which pass through an intermediate collar 0 and engage in agroove in the base 0. Beneath collar 0 is a horizontal plate 0 held byscrew bolts (1', which pass through collar 0 into the flange of thepulley G. This plate has a series of perforations 6, so that waterdelivered into the chamber above the plate will be supplied in regulatedquantity around the rim of the wheel 0, and spread thence over thesurface of the work beneath it.

Between the collar 0 and the flange of the pulley G is set a steelbearing ring I-I having upper and lower inclined bearing surfaces. Thesesurfaces bear against two sets of friction-balls ff. The upper setftakesthe end thrust of the wheel when grinding, and the lower setf sustainsthe weight and downward pressure of the wheel. The friction balls f f aswell as hearing rings h, h are contained in a recessed or chambered ringI which is attached by bolts 2' t" to the ears J on bed B, and isadjustable as presently explained. The balls are in contact with thebearing rings h h which are angular in cross section so as to presenttwo contact surfaces to the balls. This construction is of someimportance, because when friction-balls have contact with two surfacesonly they wear untrue in a short time. As shown, the ballsf f touch atthree points, one on ring H and two on ring h or it, and by constantlyrolling on these three surfaces they wear evenly, and obviate a loosejoint, which would result in end play. Ring h is carried by a clampingcollar 71?, which is screwed into ring 1 and clamps the bearing ring Hfirmly between its two sets of balls h it, so that the grinding wheelcannot play in the direction of its axis. The importance of thisresultin the operation of cup-grinders has already been pointed out. Thesupport I of the wheel is pivoted on the screw-bolts i in ears J, asalreadystated. The bolts 7; pass through curved slots j in the ears J(Fig. I). By loosening bolts t" the support I with the wheel can betilted at any desired inclination to the work holding table, thusenabling the machine to execute certain classes of concave or convexgrinding. The grinding wheel is driven in either direction through themedium of arope or cord which passes around pulleys K K supported inbearings upon, and movable with, the bed B, and also around the groovedpulley G attached to wheel 0. The vertical column F supports ahorizontal table or bed F which, as shown has longitudinal dovetailedgrooves in its upper surface, into which can be fitted work-holders ofdifferent kinds according to the work to be done. Column F has at itsupper part an outer cylinder F whiclnextends downwardly past the bottomof the hollow bed B acting as a guard to the water which flows off tableF and is caught by a drip pan L. The water escapes at the center of thispan through an annular opening Z around cylinder F into a basin L whichis part of the main frame, and thence is discharged through apipe Z(Fig. III). 001- umn F fits inside a sleeve M, which is also part of themain frame and is prevented from turning therein by a keym. Cylinder Ffits outside this sleeve, whichconstitutes aguide to the column in itsvertical adjustment. This adjustment to compensate for wear is effectedautomatically by mechanism similar in principle to that described in myapplication filed October 18, 1892, Serial No. 449,249. Movement isimparted to the column by a screw M which has on its lower end a bevelgear M engaged and driven by a pinion 'm on spindle 4% (Figs. I and 1V).Spindle m is actuated through pinions n n the latter being on a shortshaft M, to which may be fitted a crank-handle N as shown in Fig. I whenthe column is to be raised or lowered by hand for the purpose of initialadjustment. During the operation of the grinder the shaft n is movedintermittently through a pawl 0 which engages a ratchet wheel 0' onshaft n Pawl o is carried by a plate 0 swung loosely on shaft n to whichis pivoted one end of a pitman O. The other end of the pitman isconnected to a pin 0 set eccentrically in a T- groove 0 on the face of adisk 0, the pin being adjustable in said groove to vary; the throw ofthe pitman. Disk 0 is attached to a collarp (Fig. V) which embraces aboss 19' on the end of an oscillatory shaft P, which communicatesreciprocatory movements to bed B, as presently explained. Collar p holdsto boss 10' by friction only, so that the operation of raising thework-holding column is as follows: Disk 0' turns with shaft P, advancingpitman O and then withdrawing it, until an arm 0 carried by disk 0strikes a pin 0 in the frame A (Fig. I) when the disk stops and isstationaryduring the remainder of the feed in that direction. When theshaft P reverses the same action takes place until disk 0', now movingin the opposite direction, is again: arrested by pin 0 A nut 0 providedwith a handle is shown on the end of pin 0 IIO for clamping the pin toand releasing it from the disk.

Motion is communicated to the bed B by means of automatic feed-mechanismwhich I.

will now describe. This mechanism is the same in principle asthatdescribed in my aforesaid Patent No. 465,47 8. Q is the main shafthaving pinions q q. Pinion q drives directly a gear 1", loose on shaftP, and pinion q drives, through an intermediate pinion g a gear 'r' alsoloose on shaft P. Gears 1" 1" therefore turn in opposite directions.Shaft P receives motion alternately from these gears through the actionof a sliding clutch R mounted on shaft P between the gears r r slide R.The latter hason each side pins 3 adapted to engage similar pins 8' onthe inner faces of gears r r as described in my last named patent.Clutch or slideR is actuated 1 by an arm S (Fig. III) having a forkedend which embraces a groove in said slide, said,

.S' has another arm S to which the end .9

(Fig. V) of a pitman S (Figs. I and IV) is pivoted. The other'end ofthis pitman is connected to the vertical lever S whose free end S liesin the path of the adjustable stops S S on bed B. Consequently, by thecontact of these stops with lever S the clutch R is shifted reversingthe movements of the wheel. To insure the reversal of the feedmotion,the end of arm S is provided with a spring actuated pin S (Fig.VI) whose point bears in a hole in the main-frame A (Fig. V) so that thespring acts to snap the arm S one way or the other, as soon as rockshaft Shas passed the center, completing the movement of the clutch byaquick action. Shaft Ptransmits motion to bed B through pinion t, gear T,pinion t,

and gear T. The latter engages arack T on the under side of thehorizontal rib b of bed B. Gear T is mounted on a shafto which alsocarries pinion t the latter being connected to the shaft by a slipkey 1) (Fig. V) extending through a bearing plate V. The outer end ofshafto is screw threaded and its inner end carries a disk 41 set intothe side of gear T. A clamping nut V adapted to be turned by hand isscrewed on the end of shafto and by it gear T is normally clampedtightly between the disk 22 and pinion t, but by unscrewing the nut 41the gear T is made loose, and will rotate idly. This is done when it isdesired to disconnect the automatic feed mechanism and reciprocate thebed by hand in executing special kinds of work. For operating the feedby hand a crank W (Fig. I) is provided connected with a shaft to whichcarries a pinion w meshing with gear T, the latter being in engagementwith the rack T as already pointed out.

It will be obvious from an inspection of the drawings that the specialconstruction and arrangement of parts shown and described, constitute agrinding machine of great compactness, strength and efficiency andwith'little complication. Through the opening D in It will be obviousthat some of the improvelnents described can be used without others,

if so desired; and that modifications may be made without departing fromthe spirit of the invention; as for instance, the whole rotating part towhich the grinding wheel is attached may be in one piece made of anysuitable hard'material such as hardened steel in which case there wouldbe no separate ring for the ball bearings.

What I claim as my invention, and desire to secure by Letters Patent,is 1. In a grinding machine the combination with a horizontalwork-holding table, of a. hollow reciprocating bed, a ring-grindersupported in an inverted position upon said bed and having its grindingface inclosed thereby, means for rotating said grinder and means forreciprocating said bed, substantially as described.

2. The combination with a horizontal workholding table, of a hollowreciprocating bed and a rotating ring-grinder carried by said bed andhaving its grinding surface inclosed thereby, said grinder beingprovided with a water chamber and passages for supplying water to theinner edge of the grinding ring, substantially as described.

. 3. The combination of the upright column or support for thework-holder, of a hollow reciprocatory bed embracing the upper part ofsaid column or support, and a grinder carried by said bed, substantiallyas described.

4. The combination of the trough-shaped main frame having horizontaledges consti-' tuting slide-ways, a hollow bed set in the main frame andadapted to slide on the edges thereof, an upright work-holder projectingthrough an opening in the underside of the bed,'and a grinder carried bythe bed above the work-holder, substantially as described.

5. The combination of the trough-shaped umn extending through saidsleeve and hfi.V-.

ing a cylinder outside of the latter, a hollow reciprocatingbedsupported upon the frame and embracing the upper part of said column,and a grinder carried by said bed, substantially as described.

7. The combination of the main-frame provided with a drip basin, andwith an upright sleeve surrounded by said basin, awork-holding columnextending through said sleeve and provided with a cylinder outside thelatter, a hollow bed movable upon said frame and embracing the upperpart of said column, and a grinder carried by said bed, substantially asdescribed.

8. The combination with a ring-grinder having its grinding surfaceundermost, of a reciprocatory bed carrying said grinder and a verticallyadjustable work-holder beneath the grinder, substantially as described.

9. The combination with the grinder, its supporting bed and means forreciprocating the bed, of awork-holder beneath the grinder, and meansfor intermittently feeding said work-holder toward the grinder,substantially as described.

10. The combination with the grinder, its supporting bed, and means forreciprocating the bed, of awork-holder beneath the grinder,intermittently acting feed-mechanism forraising the work-holder, andmeans for regulating the amount of feed at each motion, substantially asdescribed.

11. The combination with the work-holder, of an adjusting screwtherefor, gearing for turning said screw, a rod or pitman for actuatingsaid gearing, a rotatable disk, and a crank pin to which the rod orpitman is attached, adj ustably connected to said disk, substantially asdescribed.

12. The combination with a ring grinder, of a bearing ring rigidlyconnected thereto, an annularchambered supporting ring around thebearing ring, and two sets of friction balls in said chamberedsupporting ring, between which the bearing ring engages, substantiallyas described.

13. The combination with a ring grinder, of a bearing ring rigidlyconnected thereto, an annular chambered supportingring around thebearing ring, two sets of friction balls in said chambered supportingring, and an adj ustable clamping collar engaging against one set ofballs, substantially as described.

14. The combination of a vertical column for the work-holder ahorizontally reciprocating bed, a grinder carried thereby, automaticfeed-mechanism for reciprocating said bed, and means actuated fromashaft of said feedmeohanism for lifting said column, intermittently,substantially as described.

In testimony whereof I have signed this specification in the presence oftwo subscribing witnesses.

ALLEN JOHNSTON.

Witn esses:

J. T. HACKWORTH, A. G. HARROW.

